Proximity switch assembly having haptic feedback and method

ABSTRACT

A proximity switch assembly and method for detecting activation of a proximity switch assembly and providing feedback is provided. The assembly includes a plurality of proximity switches each comprising a proximity sensor providing a sense activation field. The assembly also includes control circuitry processing a signal associated with the activation field of each proximity sensor and detecting a finger located between two proximity switches. The assembly further includes a feedback device generating a feedback when the finger is detected between the two proximity switches. In addition, the assembly may detect speed of movement of a finger interfacing with the proximity switches and vary the feedback based on the detected speed.

FIELD OF THE INVENTION

The present invention generally relates to switches, and moreparticularly relates to proximity switches having an enhanceddetermination of switch activation and feedback.

BACKGROUND OF THE INVENTION

Automotive vehicles are typically equipped with various user actuatableswitches, such as switches for operating devices including poweredwindows, headlights, windshield wipers, moonroofs or sunroofs, interiorlighting, radio and infotainment devices, and various other devices.Generally, these types of switches need to be actuated by a user inorder to activate or deactivate a device or perform some type of controlfunction. Proximity switches, such as capacitive switches, employ one ormore proximity sensors to generate a sense activation field and sensechanges to the activation field indicative of user actuation of theswitch, typically caused by a user's finger in close proximity orcontact with the sensor. Capacitive switches are typically configured todetect user actuation of the switch based on comparison of the senseactivation field to a threshold.

Switch assemblies often employ a plurality of capacitive switches inclose proximity to one another and generally require that a user selecta single desired capacitive switch to perform the intended operation. Insome applications, such as use in an automobile, the driver of thevehicle has limited ability to view the switches due to driverdistraction. In such applications, it is desirable to allow the user toexplore the switch assembly for a specific button while avoiding apremature determination of switch activation. Thus, it is desirable todiscriminate whether the user intends to activate a switch, or is simplyexploring for a specific switch button while focusing on a higherpriority task, such as driving, or has no intent to activate a switch.Accordingly, it is desirable to provide for a proximity switcharrangement which enhances the use of proximity switches by a person,such as a driver of a vehicle.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a proximity switchassembly is provided. The proximity switch assembly includes a pluralityof proximity switches each comprising a proximity sensor providing asense activation field. The proximity switch assembly also includescontrol circuitry processing a signal associated with the senseactivation field of each proximity sensor and detecting a finger locatedbetween two proximity switches. The proximity switch assembly furtherincludes a feedback device generating a feedback when the finger isdetected between the two proximity switches.

According to another aspect of the present invention, a proximity switchassembly is provided. The proximity switch assembly includes a pluralityof proximity switches each including a proximity sensor providing asense activation field. The proximity switch assembly also includescontrol circuitry processing a signal associated with the senseactivation field of each proximity sensor and detecting speed of afinger interfacing with the proximity switches. The proximity switchassembly further includes a feedback device generating a feedback thatvaries based on the detected speed of the finger.

According to yet another aspect of the present invention, a method ofproviding feedback for a proximity switch assembly is provided. Themethod includes the steps of generating a plurality of sense activationfields with a plurality of proximity sensors associated with a pluralityof proximity switches, detecting a finger located between two proximityswitches, and generating a feedback when the finger is detected betweenthe two proximity switches.

According to a further aspect of the present invention, a method ofproviding feedback for a proximity switch assembly is provided. Themethod includes the steps of generating a plurality of sensed activationfields with a plurality of proximity sensors associated with a pluralityof proximity switches, detecting speed of movement of a fingerinterfacing with the proximity switches, and generating a feedback thatvaries based on the detected speed of the finger.

These and other aspects, objects, and features of the present inventionwill be understood and appreciated by those skilled in the art uponstudying the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a passenger compartment of an automotivevehicle having an overhead console employing a proximity switchassembly, according to one embodiment;

FIG. 2 is an enlarged view of the overhead console and proximity switchassembly shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view taken through line III-III inFIG. 2 showing an array of proximity switches in relation to a user'sfinger;

FIG. 4 is a schematic diagram of a capacitive sensor employed in each ofthe capacitive switches shown in FIG. 3;

FIG. 5 is a block diagram illustrating the proximity switch assembly,according to one embodiment;

FIG. 6 is a graph illustrating the signal count for one channelassociated with a capacitive sensor showing an activation motionprofile;

FIG. 7 is a graph illustrating the signal count for two channelsassociated with the capacitive sensors showing a slidingexploration/hunting motion profile;

FIG. 8 is a graph illustrating the signal count for a signal channelassociated with the capacitive sensors showing a slow activation motionprofile;

FIG. 9 is a graph illustrating the signal count for two channelsassociated with the capacitive sensors showing a fast slidingexploration/hunting motion profile;

FIG. 10 is a graph illustrating the signal count for three channelsassociated with the capacitive sensors in an exploration/hunting modeillustrating a stable press activation at the peak, according to oneembodiment;

FIG. 11 is a graph illustrating the signal count for three channelsassociated with the capacitive sensors in an exploration/hunting modeillustrating stable press activation on signal descent below the peak,according to another embodiment;

FIG. 12 is a graph illustrating the signal count for three channelsassociated with the capacitive sensors in an exploration/hunting modeillustrating increased stable pressure on a pad to activate a switch,according to a further embodiment;

FIG. 13 is a graph illustrating the signal count for three channelsassociated with the capacitive sensors in an exploration mode andselection of a pad based on increased stable pressure, according to afurther embodiment;

FIG. 14 is a state diagram illustrating five states of the capacitiveswitch assembly implemented with a state machine, according to oneembodiment;

FIG. 15 is a flow diagram illustrating a routine for executing a methodof activating a switch of the switch assembly, according to oneembodiment;

FIG. 16 is a flow diagram illustrating the processing of the switchactivation and switch release;

FIG. 17 is a flow diagram illustrating logic for switching between theswitch none and switch active states;

FIG. 18 is a flow diagram illustrating logic for switching from theactive switch state to the switch none or switch threshold state;

FIG. 19 is a flow diagram illustrating a routine for switching betweenthe switch threshold and switch hunting states;

FIG. 20 is a flow diagram illustrating a virtual button methodimplementing the switch hunting state;

FIG. 21 is a block diagram illustrating the proximity switch assemblyhaving feedback, according to one embodiment;

FIG. 22 is an enlarged cross-sectional view of a proximity switchassembly having an array of proximity switches in relation to a user'sfinger disposed between adjacent switches and providing a tactilefeedback;

FIG. 23 is a graph illustrating the signal count for three signalchannels associated with the capacitive sensors showing the user'sfinger sliding among adjacent proximity switches of FIG. 22; and

FIGS. 24A and 24B is a flow diagram illustrating a feedback controlroutine for providing feedback to the user, according to one embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousand alternative forms. The figures are not necessarily to a detaileddesign; some schematics may be exaggerated or minimized to show functionoverview. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

Referring to FIGS. 1 and 2, the interior of an automotive vehicle 10 isgenerally illustrated having a passenger compartment and a switchassembly 20 employing a plurality of proximity switches 22 having switchactivation monitoring and determination, according to one embodiment.The vehicle 10 generally includes an overhead console 12 assembled tothe headliner on the underside of the roof or ceiling at the top of thevehicle passenger compartment, generally above the front passengerseating area. The switch assembly 20 has a plurality of proximityswitches 22 arranged close to one another in the overhead console 12,according to one embodiment. The various proximity switches 22 maycontrol any of a number of vehicle devices and functions, such ascontrolling movement of a sunroof or moonroof 16, controlling movementof a moonroof shade 18, controlling activation of one or more lightingdevices such as interior map/reading and dome lights 30, and variousother devices and functions. However, it should be appreciated that theproximity switches 22 may be located elsewhere on the vehicle 10, suchas in the dash panel, on other consoles such as a center console,integrated into a touch screen display 14 for a radio or infotainmentsystem such as a navigation and/or audio display, or located elsewhereonboard the vehicle 10 according to various vehicle applications.

The proximity switches 22 are shown and described herein as capacitiveswitches, according to one embodiment. Each proximity switch 22 includesat least one proximity sensor that provides a sense activation field tosense contact or close proximity (e.g., within one millimeter) of a userin relation to the one or more proximity sensors, such as a swipingmotion by a user's finger. Thus, the sense activation field of eachproximity switch 22 is a capacitive field in the exemplary embodimentand the user's finger has electrical conductivity and dielectricproperties that cause a change or disturbance in the sense activationfield as should be evident to those skilled in the art. However, itshould also be appreciated by those skilled in the art that additionalor alternative types of proximity sensors can be used, such as, but notlimited to, inductive sensors, optical sensors, temperatures sensors,resistive sensors, the like, or a combination thereof. Exemplaryproximity sensors are described in the Apr. 9, 2009, ATMEL® TouchSensors Design Guide, 10620 D-AT42-04/09, the entire reference herebybeing incorporated herein by reference.

The proximity switches 22 shown in FIGS. 1 and 2 each provide control ofa vehicle component or device or provide a designated control function.One or more of the proximity switches 22 may be dedicated to controllingmovement of a sunroof or moonroof 16 so as to cause the moonroof 16 tomove in an open or closed direction, tilt the moonroof, or stop movementof the moonroof based upon a control algorithm. One or more otherproximity switches 22 may be dedicated to controlling movement of amoonroof shade 18 between open and closed positions. Each of themoonroof 16 and shade 18 may be actuated by an electric motor inresponse to actuation of the corresponding proximity switch 22. Otherproximity switches 22 may be dedicated to controlling other devices,such as turning an interior map/reading light 30 on, turning an interiormap/reading light 30 off, turning a dome lamp on or off, unlocking atrunk, opening a rear hatch, or defeating a door light switch.Additional controls via the proximity switches 22 may include actuatingdoor power windows up and down. Various other vehicle controls may becontrolled by way of the proximity switches 22 described herein.

Referring to FIG. 3, a portion of the proximity switch assembly 20 isillustrated having an array of three serially arranged proximityswitches 22 in close relation to one another in relation to a user'sfinger 34 during use of the switch assembly 20. Each proximity switch 22includes one or more proximity sensors 24 for generating a senseactivation field. According to one embodiment, each of the proximitysensors 24 may be formed by printing conductive ink onto the top surfaceof the polymeric overhead console 12. One example of a printed inkproximity sensor 24 is shown in FIG. 4 generally having a driveelectrode 26 and a receive electrode 28 each having interdigitatedfingers for generating a capacitive field 32. It should be appreciatedthat each of the proximity sensors 24 may be otherwise formed such as byassembling a preformed conductive circuit trace onto a substrateaccording to other embodiments. The drive electrode 26 receives squarewave drive pulses applied at voltage V_(I). The receive electrode 28 hasan output for generating an output voltage V_(O). It should beappreciated that the electrodes 26 and 28 may be arranged in variousother configurations for generating the capacitive field as theactivation field 32.

In the embodiment shown and described herein, the drive electrode 26 ofeach proximity sensor 24 is applied with voltage input V_(I) as squarewave pulses having a charge pulse cycle sufficient to charge the receiveelectrode 28 to a desired voltage. The receive electrode 28 therebyserve as a measurement electrode. In the embodiment shown, adjacentsense activation fields 32 generated by adjacent proximity switches 22overlap slightly, however, overlap may not exist according to otherembodiments. When a user or operator, such as the user's finger 34,enters an activation field 32, the proximity switch assembly 20 detectsthe disturbance caused by the finger 34 to the activation field 32 anddetermines whether the disturbance is sufficient to activate thecorresponding proximity switch 22. The disturbance of the activationfield 32 is detected by processing the charge pulse signal associatedwith the corresponding signal channel. When the user's finger 34contacts two activation fields 32, the proximity switch assembly 20detects the disturbance of both contacted activation fields 32 viaseparate signal channels. Each proximity switch 22 has its own dedicatedsignal channel generating charge pulse counts which is processed asdiscussed herein.

Referring to FIG. 5, the proximity switch assembly 20 is illustratedaccording to one embodiment. A plurality of proximity sensors 24 areshown providing inputs to a controller 40, such as a microcontroller.The controller 40 may include control circuitry, such as amicroprocessor 42 and memory 48. The control circuitry may include sensecontrol circuitry processing the activation field of each sensor 22 tosense user activation of the corresponding switch by comparing theactivation field signal to one or more thresholds pursuant to one ormore control routines. It should be appreciated that other analog and/ordigital control circuitry may be employed to process each activationfield, determine user activation, and initiate an action. The controller40 may employ a QMatrix acquisition method available by ATMEL®,according to one embodiment. The ATMEL acquisition method employs aWINDOWS® host C/C++ compiler and debugger WinAVR to simplify developmentand testing the utility Hawkeye that allows monitoring in real-time theinternal state of critical variables in the software as well ascollecting logs of data for post-processing.

The controller 40 provides an output signal to one or more devices thatare configured to perform dedicated actions responsive to correctactivation of a proximity switch. For example, the one or more devicesmay include a moonroof 16 having a motor to move the moonroof panelbetween open and closed and tilt positions, a moonroof shade 18 thatmoves between open and closed positions, and lighting devices 30 thatmay be turned on and off Other devices may be controlled such as a radiofor performing on and off functions, volume control, scanning, and othertypes of devices for performing other dedicated functions. One of theproximity switches 22 may be dedicated to actuating the moonroof closed,another proximity switch 22 may be dedicated to actuating the moonroofopen, and a further switch 22 may be dedicated to actuating the moonroofto a tilt position, all of which would cause a motor to move themoonroof to a desired position. The moonroof shade 18 may be opened inresponse to one proximity switch 22 and may be closed responsive toanother proximity switch 22.

The controller 40 is further shown having an analog to digital (A/D)comparator 44 coupled to the microprocessor 42. The A/D comparator 44receives the voltage output V_(O) from each of the proximity switches22, converts the analog signal to a digital signal, and provides thedigital signal to the microprocessor 42. Additionally, controller 40includes a pulse counter 46 coupled to the microprocessor 42. The pulsecounter 46 counts the charge signal pulses that are applied to eachdrive electrode of each proximity sensor, performs a count of the pulsesneeded to charge the capacitor until the voltage output V_(O) reaches apredetermined voltage, and provides the count to the microprocessor 42.The pulse count is indicative of the change in capacitance of thecorresponding capacitive sensor. The controller 40 is further showncommunicating with a pulse width modulated drive buffer 15. Thecontroller 40 provides a pulse width modulated signal to the pulse widthmodulated drive buffer 15 to generate a square wave pulse train V_(I)which is applied to each drive electrode of each proximity sensor/switch22. The controller 40 processes a control routine 100 stored in memoryto monitor and make a determination as to activation of one of theproximity switches.

In FIGS. 6-13, the change in sensor charge pulse counts shown as ΔSensor Count for a plurality of signal channels associated with aplurality of proximity switches 22, such as the three switches 22 shownin FIG. 3, is illustrated according to various examples. The change insensor charge pulse count is the difference between an initializedreferenced count value without any finger or other object present in theactivation field and the corresponding sensor reading. In theseexamples, the user's finger enters the activation fields 32 associatedwith each of three proximity switches 22, generally one sense activationfield at a time with overlap between adjacent activation fields 32 asthe user's finger moves across the array of switches. Channel 1 is thechange (Δ) in sensor charge pulse count associated with a firstcapacitive sensor 24, channel 2 is the change in sensor charge pulsecount associated with the adjacent second capacitive sensor 24, andchannel 3 is the change in sensor charge pulse count associated with thethird capacitive sensor 24 adjacent to the second capacitive sensor. Inthe disclosed embodiment, the proximity sensors 24 are capacitivesensors. When a user's finger is in contact with or close proximity of asensor 24, the finger alters the capacitance measured at thecorresponding sensor 24. The capacitance is in parallel to the untouchedsensor pad parasitic capacitance, and as such, measures as an offset.The user or operator induced capacitance is proportional to the user'sfinger or other body part dielectric constant, the surface exposed tothe capacitive pad, and is inversely proportional to the distance of theuser's limb to the switch button. According to one embodiment, eachsensor is excited with a train of voltage pulses via pulse widthmodulation (PWM) electronics until the sensor is charged up to a setvoltage potential. Such an acquisition method charges the receiveelectrode 28 to a known voltage potential. The cycle is repeated untilthe voltage across the measurement capacitor reaches a predeterminedvoltage. Placing a user's finger on the touch surface of the switch 24introduces external capacitance that increases the amount of chargetransferred each cycle, thereby reducing the total number of cyclesrequired for the measurement capacitance to reach the predeterminedvoltage. The user's finger causes the change in sensor charge pulsecount to increase since this value is based on the initialized referencecount minus the sensor reading.

The proximity switch assembly 20 is able to recognize the user's handmotion when the hand, particularly a finger, is in close proximity tothe proximity switches 22, to discriminate whether the intent of theuser is to activate a switch 22, explore for a specific switch buttonwhile focusing on higher priority tasks, such as driving, or is theresult of a task such as adjusting the rearview mirror that has nothingto do with actuation of a proximity switch 22. The proximity switchassembly 20 may operate in an exploration or hunting mode which enablesthe user to explore the keypads or buttons by passing or sliding afinger in close proximity to the switches without triggering anactivation of a switch until the user's intent is determined. Theproximity switch assembly 20 monitors amplitude of a signal generated inresponse to the activation field, determines a differential change inthe generated signal, and generates an activation output when thedifferential signal exceeds a threshold. As a result, exploration of theproximity switch assembly 20 is allowed, such that users are free toexplore the switch interface pad with their fingers withoutinadvertently triggering an event, the interface response time is fast,activation happens when the finger contacts a surface panel, andinadvertent activation of the switch is prevented or reduced.

Referring to FIG. 6, as the user's finger 34 approaches a switch 22associated with signal channel 1, the finger 34 enters the activationfield 32 associated with the sensor 24 which causes disruption to thecapacitance, thereby resulting in a sensor count increase as shown bysignal 50A having a typical activation motion profile. An entry rampslope method may be used to determine whether the operator intends topress a button or explore the interface based on the slope of the entryramp in signal 50A of the channel 1 signal rising from point 52 wheresignal 50A crosses the level active (LVL_ACTIVE) count up to point 54where signal 50A crosses the level threshold (LVL_THRESHOLD) count,according to one embodiment. The slope of the entry ramp is thedifferential change in the generated signal between points 52 and 54which occurred during the time period between times t_(th) and t_(ac).Because the numerator level threshold—level active generally changesonly as the presence of gloves is detected, but is otherwise a constant,the slope can be calculated as just the time expired to cross from levelactive to level threshold referred to as t_(active2threshold) which isthe difference between time t_(th) and t_(ac). A direct push on a switchpad typically may occur in a time period referred to t_(directpush) inthe range of about 40 to 60 milliseconds. If the timet_(active2threshold) is less than or equal to the direct push timet_(directpush), then activation of the switch is determined to occur.Otherwise, the switch is determined to be in an exploration mode.

According to another embodiment, the slope of the entry ramp may becomputed as the difference in time from the time t_(ac) at point 52 totime t_(pk) to reach the peak count value at point 56, referred to astime t_(active2peak). The time t_(active2peak). may be compared to adirect push peak, referred to as t_(direct) _(_) _(push) _(_) _(pk)which may have a value of 100 milliseconds according to one embodiment.If time t_(active2peak) is less than or equal to the t_(direct) _(_)_(push) _(_) _(pk) activation of the switch is determined to occur.Otherwise, the switch assembly operates in an exploration mode.

In the example shown in FIG. 6, the channel 1 signal is shown increasingas the capacitance disturbance increases rising quickly from point 52 topeak value at point 56. The proximity switch assembly 20 determines theslope of the entry ramp as either time period t_(active2threshold) ort_(active2peak) for the signal to increase from the first thresholdpoint 52 to either the second threshold at point 54 or the peakthreshold at point 56. The slope or differential change in the generatedsignal is then used for comparison with a representative direct pushthreshold t_(direct) _(_) _(push) or t_(direct) _(_) _(push) _(_) _(pk)to determine activation of the proximity switch. Specifically, when timet_(active2peak) is less than the t_(direct) _(_) _(push) ort_(active2threshold) is less than t_(direct) _(_) _(push), activation ofthe switch is determined. Otherwise, the switch assembly remains in theexploration mode.

Referring to FIG. 7, one example of a sliding/exploration motion acrosstwo switches is illustrated as the finger passes or slides through theactivation field of two adjacent proximity sensors shown as signalchannel 1 labeled 50A and signal channel 2 labeled 50B. As the user'sfinger approaches a first switch, the finger enters the activation fieldassociated with the first switch sensor causing the change in sensorcount on signal 50A to increase at a slower rate such that a lesseneddifferential change in the generated signal is determined. In thisexample, the profile of signal channel 1 experiences a change in timet_(active2peak) that is not less than or equal to t_(direct) _(_)_(push), thereby resulting in entering the hunting or exploration mode.Because the t_(active2threshold) is indicative of a slow differentialchange in the generated signal, no activation of the switch button isinitiated, according to one embodiment. According to another embodiment,because the time t_(active2peak) is not less than or equal to t_(direct)_(_) _(push) _(_) _(pk), indicative of a slow differential change in agenerated signal, no activation is initiated, according to anotherembodiment. The second signal channel labeled 50B is shown as becomingthe maximum signal at transition point 58 and has a rising change in Δsensor count with a differential change in the signal similar to that ofsignal 50A. As a result, the first and second channels 50A and 50Breflect a sliding motion of the finger across two capacitive sensors inthe exploration mode resulting in no activation of either switch. Usingthe time period t_(active2threshold) or t_(active2peak), a decision canbe made to activate or not a proximity switch as its capacitance levelreaches the signal peak.

For a slow direct push motion such as shown in FIG. 8, additionalprocessing may be employed to make sure that no activation is intended.As seen in FIG. 8, the signal channel 1 identified as signal 50A isshown more slowly rising during either time period t_(active2threshold)or t_(active2peak) which would result in the entering of the explorationmode. When such a sliding/exploration condition is detected, with thetime t_(active2threshold) greater than t_(direct) _(_) _(push) if thechannel failing the condition was the first signal channel entering theexploration mode and it is still the maximum channel (channel with thehighest intensity) as its capacitance drops below LVL_KEYUP_Threshold atpoint 60, then activation of the switch is initiated.

Referring to FIG. 9, a fast motion of a user's finger across theproximity switch assembly is illustrated with no activation of theswitches. In this example, the relatively large differential change inthe generated signal for channels 1 and 2 are detected, for bothchannels 1 and 2 shown by lines 50A and 50B, respectively. The switchassembly employs a delayed time period to delay activation of a decisionuntil the transition point 58 at which the second signal channel 50Brises above the first signal channel 50A. The time delay could be setequal to time threshold t_(direct) _(_) _(push) _(_) _(pk) according toone embodiment. Thus, by employing a delay time period beforedetermining activation of a switch, the very fast exploration of theproximity keypads prevents an unintended activation of a switch. Theintroduction of the time delay in the response may make the interfaceless responsive and may work better when the operator's finger motion issubstantially uniform.

If a previous threshold event that did not result in activation wasrecently detected, the exploration mode may be entered automatically,according to one embodiment. As a result, once an inadvertent actuationis detected and rejected, more caution may be applied for a period oftime in the exploration mode.

Another way to allow an operator to enter the exploration mode is to useone or more properly marked and/or textured areas or pads on the switchpanel surface associated with the dedicated proximity switches with thefunction of signaling the proximity switch assembly of the intent of theoperator to blindly explore. The one or more exploration engagement padsmay be located in an easy to reach location not likely to generateactivity with other signal channels. According to another embodiment, anunmarked, larger exploration engagement pad may be employed surroundingthe entire switch interface. Such an exploration pad would likely beencountered first as the operator's hand slides across the trim in theoverhead console looking for a landmark from which to start blindexploration of the proximity switch assembly.

Once the proximity sensor assembly determines whether an increase in thechange in sensor count is a switch activation or the result of anexploration motion, the assembly proceeds to determine whether and howthe exploration motion should terminate or not in an activation ofproximity switch. According to one embodiment, the proximity switchassembly looks for a stable press on a switch button for at least apredetermined amount of time. In one specific embodiment, thepredetermined amount of time is equal to or greater than 50milliseconds, and more preferably about 80 milliseconds. Examples of theswitch assembly operation employing a stable time methodology isillustrated in FIGS. 10-13.

Referring to FIG. 10, the exploration of three proximity switchescorresponding to signal channels 1-3 labeled as signals 50A-50C,respectively, is illustrated while a finger slides across first andsecond switches in the exploration mode and then activates the thirdswitch associated with signal channel 3. As the finger explores thefirst and second switches associated with channels 1 and 2, noactivation is determined due to no stable signal on lines 50A and 50B.The signal on line 50A for channel 1 begins as the maximum signal valueuntil channel 2 on line 50B becomes the maximum value and finallychannel 3 becomes the maximum signal value. Signal channel 3 is shownhaving a stable change in sensor count near the peak value for asufficient time period t_(stable) such as 80 milliseconds which issufficient to initiate activation of the corresponding proximity switch.When the level threshold trigger condition has been met and a peak hasbeen reached, the stable level method activates the switch after thelevel on the switch is bound in a tight range for at least the timeperiod t_(stable). This allows the operator to explore the variousproximity switches and to activate a desired switch once it is found bymaintaining position of the user's finger in proximity to the switch fora stable period of time t_(stable).

Referring to FIG. 11, another embodiment of the stable level method isillustrated in which the third signal channel on line 50C has a changein sensor count that has a stable condition on the descent of thesignal. In this example, the change in sensor count for the thirdchannel exceeds the level threshold and has a stable press detected forthe time period t_(stable) such that activation of the third switch isdetermined.

According to another embodiment, the proximity switch assembly mayemploy a virtual button method which looks for an initial peak value ofchange in sensor count while in the exploration mode followed by anadditional sustained increase in the change in sensor count to make adetermination to activate the switch as shown in FIGS. 12 and 13. InFIG. 12, the third signal channel on line 50C rises up to an initialpeak value and then further increases by a change in sensor countC_(vb). This is equivalent to a user's finger gently brushing thesurface of the switch assembly as it slides across the switch assembly,reaching the desired button, and then pressing down on the virtualmechanical switch such that the user's finger presses on the switchcontact surface and increases the amount of volume of the finger closerto the switch. The increase in capacitance is caused by the increasedsurface of the fingertip as it is compressed on the pad surface. Theincreased capacitance may occur immediately following detection of apeak value shown in FIG. 12 or may occur following a decline in thechange in sensor count as shown in FIG. 13. The proximity switchassembly detects an initial peak value followed by a further increasedchange in sensor count indicated by capacitance C_(vb) at a stable levelor a stable time period t_(stable). A stable level of detectiongenerally means no change in sensor count value absent noise or a smallchange in sensor count value absent noise which can be predeterminedduring calibration.

It should be appreciated that a shorter time period t_(stable) mayresult in accidental activations, especially following a reversal in thedirection of the finger motion and that a longer time period t_(stable)may result in a less responsive interface.

It should also be appreciated that both the stable value method and thevirtual button method can be active at the same time. In doing so, thestable time t_(stable) can be relaxed to be longer, such as one second,since the operator can always trigger the button using the virtualbutton method without waiting for the stable press time-out.

The proximity switch assembly may further employ robust noise rejectionto prevent annoying inadvertent actuations. For example, with anoverhead console, accidental opening and closing of the moonroof shouldbe avoided. Too much noise rejection may end up rejecting intendedactivations, which should be avoided. One approach to rejecting noise isto look at whether multiple adjacent channels are reporting simultaneoustriggering events and, if so, selecting the signal channel with thehighest signal and activating it, thereby ignoring all other signalchannels until the release of the select signal channel.

The proximity switch assembly 20 may include a signature noise rejectionmethod based on two parameters, namely a signature parameter that is theratio between the channel between the highest intensity (max_channel)and the overall cumulative level (sum_channel), and the dac parameterwhich is the number of channels that are at least a certain ratio of themax_channel. In one embodiment, the dac α_(dac)=0.5. The signatureparameter may be defined by the following equation:

${signature} = {\frac{max\_ channel}{sum\_ channel} = {\frac{\max_{{i = 0},n}{channel}_{i}}{\sum\limits_{i = {0.n}}^{\;}\;{channel}_{i}}.}}$

The dac parameter may be defined by the following equation:dac=∀channels _(i)>α_(dac) max_channel.

Depending on dac, for a recognized activation not to be rejected, thechannel generally must be clean, i.e., the signature must be higher thana predefined threshold. In one embodiment, α_(dac=1)=0.4, andα_(dac=2)=0.67. If the dac is greater than 2, the activation is rejectedaccording to one embodiment.

When a decision to activate a switch or not is made on the descendingphase of the profile, then instead of max_channel and sum_channel theirpeak values peak_max_channel and peak_sum_channel may be used tocalculate the signature. The signature may have the following equation:

${signature} = {\frac{{peak\_ max}{\_ channel}}{{peak\_ sum}{\_ channel}} = {\frac{\max\left( {{max\_ channel}(t)} \right)}{\max\left( {{sum\_ channel}(t)} \right)}.}}$

A noise rejection triggers hunting mode may be employed. When a detectedactivation is rejected because of a dirty signature, the hunting orexploration mode should be automatically engaged. Thus, when blindlyexploring, a user may reach with all fingers extended looking toestablish a reference frame from which to start hunting. This maytrigger multiple channels at the same time, thereby resulting in a poorsignature.

Referring to FIG. 14, a state diagram is shown for the proximity switchassembly 20 in a state machine implementation, according to oneembodiment. The state machine implementation is shown having five statesincluding SW_NONE state 70, SW_ACTIVE state 72, SW_THRESHOLD state 74,SW_HUNTING state 76 and SWITCH_ACTIVATED state 78. The SW_NONE state 70is the state in which there is no sensor activity detected. TheSW_ACTIVE state is the state in which some activity is detected by thesensor, but not enough to trigger activation of the switch at that pointin time. The SW_THRESHOLD state is the state in which activity asdetermined by the sensor is high enough to warrant activation,hunting/exploration, or casual motion of the switch assembly. TheSW_HUNTING state 76 is entered when the activity pattern as determinedby the switch assembly is compatible with the exploration/huntinginteraction. The SWITCH_ACTIVATED state 78 is the state in whichactivation of a switch has been identified. In the SWITCH_ACTIVATEDstate 78, the switch button will remain active and no other selectionwill be possible until the corresponding switch is released.

The state of the proximity switch assembly 20 changes depending upon thedetection and processing of the sensed signals. When in the SW_NONEstate 70, the system 20 may advance to the SW_ACTIVE state 72 when someactivity detected by one or more sensors. If enough activity to warranteither activation, hunting or casual motion is detected, the system 20may proceed directly to the SW_THRESHOLD state 74. When in theSW_THRESHOLD state 74, the system 20 may proceed to the SW_HUNTING state76 when a pattern indicative of exploration is detected or may proceeddirectly to switch activated state 78. When a switch activation is inthe SW_HUNTING state, an activation of the switch may be detected tochange to the SWITCH_ACTIVATED state 78. If the signal is rejected andinadvertent action is detected, the system 20 may return to the SW_NONEstate 70.

Referring to FIG. 15, the main method 100 of monitoring and determiningwhen to generate an activation output with the proximity switcharrangement is shown, according to one embodiment. Method 100 begins atstep 102 and proceeds to step 104 to perform an initial calibrationwhich may be performed once. The calibrated signal channel values arecomputed from raw channel data and calibrated reference values bysubtracting the reference value from the raw data in step 106. Next, atstep 108, from all signal channel sensor readings, the highest countvalue referenced as max_channel and the sum of all channel sensorreadings referred to as sum_channel are calculated. In addition, thenumber of active channels is determined. At step 110, method 100calculates the recent range of the max_channel and the sum_channel todetermine later whether motion is in progress or not.

Following step 110, method 100 proceeds to decision step 112 todetermine if any of the switches are active. If no switch is active,method 100 proceeds to step 114 to perform an online real-timecalibration. Otherwise, method 116 processes the switch release at step116. Accordingly, if a switch was already active, then method 100proceeds to a module where it waits and locks all activity until itsrelease.

Following the real-time calibration, method 100 proceeds to decisionstep 118 to determine if there is any channel lockout indicative ofrecent activation and, if so, proceeds to step 120 to decrease thechannel lockout timer. If there are no channel lockouts detected, method100 proceeds to decision step 122 to look for a new max_channel. If thecurrent max_channel has changed such that there is a new max_channel,method 100 proceeds to step 124 to reset the max_channel, sum theranges, and set the threshold levels. Thus, if a new max_channel isidentified, the method resets the recent signal ranges, and updates, ifneeded, the hunting/exploration parameters. If the switch status is lessthan SW_ACTIVE, then the hunting/exploration flag is set equal to trueand the switch_status is set equal to SW_NONE. If the currentmax_channel has not changed, method 100 proceeds to step 126 to processthe max_channel naked (no glove) finger status. This may includeprocessing the logic between the various states as shown in the statediagram of FIG. 14.

Following step 126, method 100 proceeds to decision step 128 todetermine if any switch is active. If no switch activation is detected,method 100 proceeds to step 130 to detect a possible glove presence onthe user's hand. The presence of a glove may be detected based on areduced change in capacitance count value. Method 100 then proceeds tostep 132 to update the past history of the max_channel and sum_channel.The index of the active switch, if any, is then output to the softwarehardware module at step 134 before ending at step 136.

When a switch is active, a process switch release routine is activatedwhich is shown in FIG. 16. The process switch release routine 116 beginsat step 140 and proceeds to decision step 142 to determine if the activechannel is less than LVL_RELEASE and, if so, ends at step 152. If theactive channel is less than the LVL_RELEASE then routine 116 proceeds todecision step 144 to determine if the LVL_DELTA_THRESHOLD is greaterthan 0 and, if not, proceeds to step 146 to raise the threshold level ifthe signal is stronger. This may be achieved by decreasingLVL_DELTA_THRESHOLD. Step 146 also sets the threshold, release andactive levels. Routine 116 then proceeds to step 148 to reset thechannel max and sum history timer for long stable signalhunting/exploration parameters. The switch status is set equal toSW_NONE at step 150 before ending at step 152. To exit the processswitch release module, the signal on the active channel has to dropbelow LVL_RELEASE, which is an adaptive threshold that will change asglove interaction is detected. As the switch button is released, allinternal parameters are reset and a lockout timer is started to preventfurther activations before a certain waiting time has elapsed, such as100 milliseconds. Additionally, the threshold levels are adapted infunction of the presence of gloves or not.

Referring to FIG. 17, a routine 200 for determining the status changefrom SW_NONE state to SW_ACTIVE state is illustrated, according to oneembodiment. Routine 200 begins at step 202 to process the SW_NONE state,and then proceeds to decision step 204 to determine if the max_channelis greater than LVL_ACTIVE. If the max_channel is greater thanLVL_ACTIVE, then the proximity switch assembly changes state fromSW_NONE state to SW_ACTIVE state and ends at step 210. If themax_channel is not greater than LVL_ACTIVE, the routine 200 checks forwhether to reset the hunting flag at step 208 prior to ending at step210. Thus, the status changes from SW_NONE state to SW_ACTIVE state whenthe max_channel triggers above LVL_ACTIVE. If the channels stays belowthis level, after a certain waiting period, the hunting flag, if set,gets reset to no hunting, which is one way of departing from the huntingmode.

Referring to FIG. 18, a method 220 for processing the state of theSW_ACTIVE state changing to either SW_THRESHOLD state or SW_NONE stateis illustrated, according to one embodiment. Method 220 begins at step222 and proceeds to decision step 224. If max_channel is not greaterthan LVL_THRESHOLD, then method 220 proceeds to step 226 to determine ifthe max_channel is less than LVL_ACTIVE and, if so, proceeds to step 228to change the switch status to SW_NONE. Accordingly, the status of thestate machine moves from the SW_ACTIVE state to SW_NONE state when themax_channel signal drops below LVL_ACTIVE. A delta value may also besubtracted from LVL_ACTIVE to introduce some hysteresis. If themax_channel is greater than the LVL_THRESHOLD, then routine 220 proceedsto decision step 230 to determine if a recent threshold event or a glovehas been detected and, if so, sets the hunting on flag equal to true atstep 232. At step 234, method 220 switches the status to SW_THRESHOLDstate before ending at step 236. Thus, if the max_channel triggers abovethe LVL_THRESHOLD, the status changes to SW_THRESHOLD state. If glovesare detected or a previous threshold event that did not result inactivation was recently detected, then the hunting/exploration mode maybe entered automatically.

Referring to FIG. 19, a method 240 of determining activation of a switchfrom the SW_THRESHOLD state is illustrated, according to one embodiment.Method 240 begins at step 242 to process the SW_THRESHOLD state andproceeds to decision block 244 to determine if the signal is stable orif the signal channel is at a peak and, if not, ends at step 256. Ifeither the signal is stable or the signal channel is at a peak, thenmethod 240 proceeds to decision step 246 to determine if the hunting orexploration mode is active and, if so, skips to step 250. If the huntingor exploration mode is not active, method 240 proceeds to decision step248 to determine if the signal channel is clean and fast active isgreater than a threshold and, if so, sets the switch active equal to themaximum channel at step 250. Method 240 proceeds to decision block 252to determine if there is a switch active and, if so, ends at step 256.If there is no switch active, method 240 proceeds to step 254 toinitialize the hunting variables SWITCH_STATUS set equal toSWITCH_HUNTING and PEAK_MAX_BASE equal to MAX_CHANNELS, prior to endingat step 256.

In the SW_THRESHOLD state, no decision is taken until a peak inMAX_CHANNEL is detected. Detection of the peak value is conditioned oneither a reversal in the direction of the signal, or both theMAX_CHANNEL and SUM_CHANNEL remaining stable (bound in a range) for atleast a certain interval, such as 60 milliseconds. Once the peak isdetected, the hunting flag is checked. If the hunting mode is off, theentry ramp slope method is applied. If the SW_ACTIVE to SW_THRESHOLD wasless than a threshold such as 16 milliseconds, and the signature ofnoise rejection method indicates it as a valid triggering event, thenthe state is changed to SWITCH_ACTIVE and the process is transferred tothe PROCESS_SWITCH_RELEASE module, otherwise the hunting flag is setequal to true. If the delayed activation method is employed instead ofimmediately activating the switch, the state is changed toSW_DELAYED_ACTIVATION where a delay is enforced at the end of which, ifthe current MAX_CHANNEL index has not changed, the button is activated.

Referring to FIG. 20, a virtual button method implementing theSW_HUNTING state is illustrated, according to one embodiment. The method260 begins at step 262 to process the SW_HUNTING state and proceeds todecision step 264 to determine if the MAX_CHANNEL has dropped below theLVL_KEYUP_THRESHOLD and, if so, sets the MAX_PEAK_BASE equal to MIN(MAX_PEAK_BASE, MAX_CHANNEL) at step 272. If the MAX_CHANNEL has droppedbelow the LVL_KEYUP_THRESHOLD, then method 260 proceeds to step 266 toemploy the first channel triggering hunting method to check whether theevent should trigger the button activation. This is determined bydetermining if the first and only channel is traversed and the signal isclean. If so, method 260 sets the switch active equal to the maximumchannel at step 270 before ending at step 282. If the first and onlychannel is not traversed or if the signal is not clean, method 260proceeds to step 268 to give up and determine an inadvertent actuationand to set the SWITCH_STATUS equal to SW_NONE state before ending atstep 282.

Following step 272, method 260 proceeds to decision step 274 todetermine if the channel clicked. This can be determined by whetherMAX_CHANNEL is greater than MAX_PEAK_BASE plus delta. If the channel hasclicked, method 260 proceeds to decision step 276 to determine if thesignal is stable and clean and, if so, sets the switch active state tothe maximum channel at step 280 before ending at step 282. If thechannel has not clicked, method 260 proceeds to decision step 278 to seeif the signal is long, stable and clean, and if so, proceeds to step 280to set the switch active equal to the maximum channel before ending atstep 282.

Accordingly, the determination routine advantageously determinesactivation of the proximity switches. The routine advantageously allowsfor a user to explore the proximity switch pads which can beparticularly useful in an automotive application where driverdistraction can be avoided.

A proximity switch assembly 20 and method of activating a proximityswitch assembly is illustrated in FIGS. 21-24B providing one or morefeedbacks, such as tactile feedback, to a user interfacing with theswitch assembly 20, according to one embodiment. The proximity switchassembly 20 includes a plurality of proximity switches each comprising aproximity sensor shown as proximity sensors 24A-24X for providing asense activation field and control circuitry processing a signalassociated with the sense activation field of each proximity sensor. Thecontrol circuitry may detect a user's finger located between twoproximity switches such as when the finger slides across the interfacesurface and transitions from a first proximity switch to a secondproximity switch. The proximity switch assembly further includes afeedback device generating a feedback when the finger is detectedbetween the two proximity switches. The feedback device provides atleast one feedback, such as a tactile feedback according to oneembodiment. The feedback device may include a vibratory mechanism, suchas an eccentric motor. The amplitude, pattern and/or frequency of thevibration may be varied to provide different recognizable feedbacks. Inone embodiment, the feedback device provides a tactile feedback to theuser when the user's finger is detected moving or transitioning midwaybetween two adjacent switches. The control circuitry may also detectspeed of the user's finger interfacing with the proximity switchassembly and may generate a feedback that varies in amplitude orfrequency based on the detected speed. In addition, feedback may also beprovided when an activation of one of the proximity switches isdetected, when a user taps on one of the switches, and/or when a userreleases one of the proximity switches. In addition to a tactilefeedback, other feedbacks may be employed including an audible tonegenerated by an audible tone generator, and a visual feedback, such asan indicator light. The tactile feedback device may be located withinthe proximity switch assembly housing, according to one embodiment.According to other embodiments, the tactile feedback device may belocated elsewhere such as in the driver's seat or steering wheel.

Referring to FIG. 21, the proximity switch assembly 20 is illustratedhaving a plurality of proximity sensors 24A-24X associated with aplurality of proximity switches 22 as described herein. The controller40 receives a signal associated with each of the proximity sensors24A-24X and processes the signals and one or more control routinesstored in memory 48 with microprocessor 42. Controller 40 providesoutput signals to various devices, such as the moonroof 16, moonroofshade 18, and lighting device(s) 30. In addition, one or more feedbackdevices 300 receive outputs from the controller 40 to generate one ormore feedbacks to a user. The feedback devices 300 may include anaudible tone generator 302 for generating an audible feedback such asone or more vehicle speakers installed in the doors or elsewhere on thevehicle that may generate one or more tones. Any of the vehicle equippedspeakers or other audible tone generators may be employed to provide anaudible tone to the user as a feedback based on user interaction withthe proximity switch assembly 20. Other feedback devices may include avisual display 304 generating a visual feedback, such as a navigation orradio display installed in the vehicle. The visual display 304 maydisplay text or icons as feedback indicative of feedback for theproximity switch assembly 20. Further feedback devices may include avibratory/tactile generator 306 for providing a tactile feedback such asvibrations that are sensed and recognizable by a user. Thevibratory/tactile generator 306 may be implemented as an eccentricmotor, according to one embodiment. The vibratory/tactile generator 306may be integrated within a housing of the proximity switch assembly 20or within the individual proximity switches 22 to generate vibration orsensation that may be recognized by the user's finger, according to oneembodiment. According to other embodiments, the vibratory/tactilegenerator 306 may be located within the steering wheel of the vehicle,the vehicle seat, or other point of contact with the user to provide avibration or sensation that is perceived by the user upon a particularinteraction with the proximity switch assembly 20. A further visualfeedback device may include one or more indicator lights 308 forproviding a visual light indication as a feedback indicative of a user'sinteraction with the proximity switch assembly 20. The indicatorlight(s) 308 may include a dedicated light installed in the instrumentpanel cluster, or other dedicated or shared lighting devices includingmood or ambient lighting, dome lighting, map reading lights, electronicdisplay lighting and other lighting available and viewable by a user ofthe proximity switch assembly 20. The controller 40 processes thesignals generated by the proximity sensors 24A-24X and generates one ormore feedback signals to provide feedback to the user via the feedbackdevices 300 as described herein.

Referring to FIG. 22, a portion of the proximity switch assembly 20 isillustrated having three serially arranged proximity switches 22A-22C inclose relation to one other and further in relation to a user's finger34 during an interaction of the finger 34 interfacing with the proximityswitch assembly 20. Each proximity switch 22A-22C includes one or moreproximity sensors 24A-24C for generating a sense activation field 32.The proximity switches 22A-22C are generally provided in a housing, suchas the overhead console 12 which is shown having a substantially flat orplanar outer surface that forms the contact/interfacing surface or padfor activating the proximity switches 24A-24C. The proximity sensors22A-22C are formed on the inside surface of the housing in theembodiment shown.

As the user's finger 34 interfaces with the proximity switch assembly 20and slides across the interface from the first proximity switch 22A tothe third proximity switch 22C, the assembly 20 generates thecorresponding three signal channels 50A-50C as shown in FIG. 23. In thisexample, the finger 34 is exploring the interface in thehunting/exploration mode and initially causes the generation of thefirst signal channel 58 corresponding to proximity switch 22A, whichrises up and drops down in an approximate bell shape. Each of the secondproximity switch 22B and third proximity switch 22C likewise generatessecond and third signal channels 50B and 50C, respectively, as thefinger continues to slide across the interface in the exploration mode.When the finger 34 transitions to a point midway between two adjacentproximity switches, such as the midpoint between the first proximityswitch 22A and the second proximity switch 22B, the first and secondsignals 50A and 50B intersect at the same value shown at transitionpoint 58. When the finger 34 is midway between two adjacent proximityswitches at transition point 58, the proximity switch assembly 20generates a first feedback, such as a tactile feedback generated by thevibratory/tactile generator to signal the user that the finger hastransitioned between two proximity switches. The first feedback therebyprovides a recognizable sensation to the user that the finger istransitioning from one proximity switch to another proximity switch tosimulate a switch border without requiring a surface contour change,such as a mechanical ridge. By eliminating the need for a mechanicalridge in the contact surface, a more streamlined contact surface may beemployed with the proximity switch assembly 20.

It should be appreciated that the information collected and generated bythe proximity switch assembly 20 that processes the various signalsgenerated by the proximity sensors 24A-24X may be used to providevarious feedbacks, such as tactile feedbacks, to the user. The firstfeedback may be the tactile feedback that is provided when the finger isdetected between two adjacent proximity switches. A second feedback mayinclude a feedback that varies in amplitude or frequency as a functionof detected speed of movement of the finger as it interfaces with theproximity switches. Further feedbacks may include a third feedback thatis applied when an activation of a proximity switch is detected. Afurther feedback may include a fourth feedback that is applied when auser is detected tapping on one of the switches. Yet a fifth feedbackmay include a feedback generated when a release of one of the proximityswitches is detected.

It should be appreciated that any of the various conditions detected bythe proximity switch assembly and method as described herein may beemployed to generate one or more feedbacks to a user to provide aparticular response to a condition detected by the assembly 20. Itshould be appreciated that the various first, second, third, fourth andfifth feedbacks may have different characteristics, such as the lengthof the feedback, or a pattern such as a coded sequence of activationsincluding short and long activations in series, or amplitude of thefeedback, or a frequency of the feedback. For example, if a press on aproximity switch is detected, the proximity switch assembly 20 maygenerate a sensation of a “click.” If the assembly detects that the useris interacting with more than one sensor associated with more than oneproximity switch, such as when sliding on the contact surface, the stateof the assembly 20 switches to a hunting or exploration mode. In theexploration mode, a more simple tap and stable press may becomedisabled. Instead, the assembly may wait for the user to stop sliding,thereby checking for a relative “stable” output from the proximitysensors. As a stable output is achieved, the assembly 20 may determinethat the user's finger is interfacing with a sensor by checking thesignature ratio, which is the ratio of the largest channel divided bythe cumulative of the remaining signal channels, or between sensors. Ifthe user is detected interfacing with a sensor, a specific tactileprofile feedback can be produced to simulate the feel of a “detent”typically carved on the bottom of the contact surface to help guide thefinger to it. As the user increases the finger pressure on the contactsurface aligned with the particular switch, it generates an additionalamplitude in the signal which triggers an activation, and thus mayrender another tactile profile feedback for this condition. When in theexploration mode, by checking when a neighboring pad signal overcomesthe dominant current signal channel, the assembly can determine when theuser slides across the contact surface or pads. This condition cantrigger the rendering of a “ridge” profile feedback. This allows for thebenefit of a possibility of an entirely flat surface, which may be moreaesthetically appealing and cheaper to manufacture, while stillproviding the feeling of passing over a physical ridge when skimmingover the surface with a finger.

In between proximity switches, the assembly 20 can further detect notonly that the finger is moving by monitoring whether the proximitysignals are stable or not, but also can infer the travel speed of thefinger across the surface by estimating the rate of change of thecurrent dominant (max) signal for the current proximity switch and theadjacent neighboring proximity switch. The speed of change may be usedto control the timing and amplitude of a “textured” rendering profileapplied by the vibratory/tactile generator. The vibratory/tactilegenerator could be driven by a saw-tooth or a square-wave pulsemodulated train with duty cycle, pulsed, overlapped duration andintensity as selectable parameters to implement the different profilessuch as the “ridge,” “button-tap,” “button-press,” and “texture”profiles.

Referring to FIGS. 24A-24B, the feedback control routine 400 is shownfor monitoring and determining when to generate a haptic feedback,according to one embodiment. It should be appreciated that the feedbackcontrol routine 400 processes the data that is monitored and processedin control routines described herein including the routine shown in FIG.15. As such, the microprocessor processes the various routinessimultaneously in parallel or in series. Method 400 begins at step 402and proceeds to step 404 to determine if the new maximum signal channelhas experienced a transition from one signal channel to another signalchannel. If a new maximum signal channel transition has occurred,indicative of the user's finger transitioning from a first proximityswitch to a second proximity switch, then routine 400 proceeds to step406 to generate a haptic feedback for a “ridge” profile. As such,routine 400 generates a feedback to the user to simulate the presence ofa mechanical ridge when a finger transitions between adjacent proximityswitches. Thereafter, routine 400 ends at step 438.

If there was no new max signal channel transition detected in step 404,routine 400 proceeds to decision step 408 to determine if a stable pressor a virtual button press has been detected. If a stable press or avirtual button press has been detected, routine 400 proceeds to step 410to generate a haptic feedback for a “button pressed” profile, beforeending at step 438. Accordingly, a separate feedback is generatedindicative of a button press by the user.

If there was no stable press or virtual button press detected in step408, routine 400 proceeds to decision step 412 to determine if a tappress has been detected. If a tap press has been detected, routine 400proceeds to step 414 to generate a haptic feedback for a “button tap”profile before ending at step 438. As such, detection of a tap pressresults in a generation of a button tapped profile being generated forthe user.

If a tap press has not been detected in step 412, routine 400 proceedsto decision step 416 to determine if the switch having an active signalhas been released. If such a switch has been released, routine 400proceeds to step 412 to generate a haptic feedback for a “buttonreleased” profile before ending at step 438. As such, when a useractivates a switch and holds onto it and then releases the switch, thiscauses the generation of a button released feedback to the user so thatthe user can acknowledge that the release has occurred. Such a buttonreleased feedback may include an illuminated light or an audible tonesince the user's finger may disengage the contact surface or pad.

If a switch release has not been detected in step 416, routine 400proceeds to decision step 420 to determine if a virtual button has beeninitialized. If a virtual button has been initialized, routine 400proceeds to step 422 to generate a haptic feedback for a “buttondetected” profile, before ending at step 438. As such, the virtualbutton initialization results in the generation of a button detectedfeedback that is detectable by the user.

If no virtual button initialization has been detected in step 420,routine 400 proceeds to decision step 424 to determine if the switchstate is set equal to the switch SW none state which is indicative of nosignificant activity on the proximity switch assembly. If the switchstate is set equal to switch SW_none, routine 400 proceeds to step 428to turn the haptic feedback devices off before ending at step 438.Similarly, at decision step 428, routine 400 determines if the switchstate is in the active switch SW_Active state and, if so, proceeds tostep 428 to turn the haptics off before ending at step 438.

If the state is not set equal to switch active SW_Active state, routine400 proceeds decision step 430 to determine if the state is set equal tothe switch threshold SW_Threshold state. If the state is set equal toswitch threshold SW_Threshold, routine 400 proceeds to step 434 tocalculate speed of the user's finger interfacing with the proximityswitches as a function of a signal ratio delta value. The signal ratiodelta value may be indicative of the speed of the interfacing fingermoving on or across the proximity switch assembly. The speed of thefinger may be determined by monitoring the rate of change of the signalas it progresses from one proximity switch to another proximity switch.After calculating the speed based on the signal ratio delta value,routine 400 proceeds to decision step 436 to generate a haptic feedbackthat varies based on the speed of movement of the finger. This hapticfeedback may include a change in the vibration frequency which may varyas a function of the detected speed of motion of the finger. Forexample, if the finger moves faster on the proximity switch assembly,the frequency of the signal may be increased, whereas if the fingermoves slower, the proximity switch frequency may decrease. Incombination or alternatively, the amplitude of the signal may changesuch that a faster moving signal causes a higher amplitude, whereas aslower moving finger causes a lower amplitude signal. Followingactivation of this haptic in block 436, routine 400 ends at step 438.

If the state is not equal to the switch threshold state in decisionblock 430, routine 400 proceeds to decision block 432 to determine ifthe state is equal to the switch exploration/hunting state. If the stateis set equal to the switch exploration/hunting state, routine 400proceeds to step 434 to calculate the signal ratio delta value and thento generate the haptic signal in step 436 before ending at step 438.

Accordingly, the proximity switch assembly and method according to theembodiment shown in FIGS. 21-24B advantageously provides one or morefeedbacks to a user indicative of the activation or interfacing of auser's finger with the assembly. The proximity switch assembly mayprovide a feedback indicative of the border between adjacent proximityswitches, thereby eliminating the need for physical ridge or other aphysical markings on the contact surface. Further feedbacks can begenerated for various other types of activations and other profileswhich may occur with various different activation amplitudes,frequencies, time periods, and/or patterns, thereby allowing the user todetermine which type of feedback is occurring.

It is to be understood that variations and modifications can be made onthe aforementioned structure without departing from the concepts of thepresent invention, and further it is to be understood that such conceptsare intended to be covered by the following claims unless these claimsby their language expressly state otherwise.

What is claimed is:
 1. A proximity switch assembly comprising: aplurality of proximity switches each comprising a proximity sensorproviding a sense activation field; control circuitry processing asignal associated with the sense activation field of each proximitysensor and detecting a finger transitioning between two proximityswitches; and a feedback device generating a tactile or audible feedbackwhen the finger is detected transitioning from first to second proximityswitches in a region therebetween without selecting the switches.
 2. Theproximity switch assembly of claim 1, wherein the feedback deviceprovides a tactile feedback.
 3. The proximity switch assembly of claim2, wherein the feedback device comprises a vibratory mechanism.
 4. Theproximity switch assembly of claim 1, wherein the feedback devicegenerates at least one of a tactile feedback, an audible feedback, and avisual feedback.
 5. The proximity switch assembly of claim 1, whereinthe plurality of proximity switches comprises the first proximity switchlocated adjacent to the second proximity switch, wherein the controlcircuitry detects when the finger transitions midway between the firstand second proximity switches.
 6. The proximity switch assembly of claim1, wherein the feedback device generates a first feedback when thefinger is detected transitioning from the first proximity switch to thesecond proximity switch, and further generates a second feedback whenthe control circuitry detects an activation of one of the proximityswitches.
 7. The proximity switch assembly of claim 1, wherein thecontrol circuitry generates a feedback that varies as a function ofspeed of the finger moving across the plurality of proximity switches.8. The proximity switch assembly of claim 1, wherein the plurality ofproximity switches are installed in a vehicle for use by a passenger ofthe vehicle.
 9. The proximity switch assembly of claim 1, wherein theplurality of proximity switches comprises a plurality of capacitiveswitches each comprising one or more capacitive sensors.
 10. A proximityswitch assembly comprising: a plurality of proximity switches eachcomprising a proximity sensor providing a sense activation field;control circuitry processing a signal associated with the senseactivation field of each proximity sensor and detecting speed of afinger moving across the proximity switches; and a feedback devicegenerating a tactile or audible feedback when the finger istransitioning from first to second proximity switches in a regiontherebetween and that varies based on the detected speed of the fingermoving across the proximity switches without selecting the switches. 11.The proximity switch assembly of claim 10, wherein the control circuitryfurther detects a finger transitioning between two proximity switchesand generates a feedback when the finger is detected transitioningmidway from a first proximity switch to a second proximity switch.
 12. Amethod of providing feedback for a proximity switch assembly comprising:generating a plurality of sense activation fields with a plurality ofproximity sensors associated with a plurality of proximity switches;detecting a finger transitioning from a first proximity switch to asecond proximity switch; and generating a tactile or audible feedbackwhen the finger is detected transitioning from first to second proximityswitches in a region therebetween without selecting the switches. 13.The method of claim 12, wherein the feedback comprises a tactilefeedback.
 14. The method of claim 13, wherein the tactile feedback isgenerated by a vibratory mechanism.
 15. The method of claim 12, whereinthe feedback device generates at least one of a tactile feedback, anaudible tone feedback and a visual feedback.
 16. The method of claim 12,wherein the feedback comprises a first feedback generated when thefinger is transitioning from the first proximity switch to the secondproximity switch, and further comprises a second feedback whenactivation of one of the proximity switches is detected.
 17. The methodof claim 12 further comprising the step of detecting speed of movementof the finger across the plurality of proximity switches and varying thefeedback as a function of the detected speed.
 18. The method of claim12, wherein the proximity switch assembly is installed on a vehicle foruse by a passenger in the vehicle.
 19. The method of claim 12, whereinthe proximity switch assembly comprises a capacitive switch comprisingone or more capacitive sensors.
 20. A method of providing feedback for aproximity switch assembly comprising: generating a plurality of senseactivation fields with a plurality of proximity sensors associated witha plurality of proximity switches; detecting speed of movement of afinger moving across the proximity switches; and generating a tactile oraudible feedback when the finger is transitioning from first to secondproximity switches in a region therebetween and that varies based on thedetected speed of the finger moving across the proximity switcheswithout selecting the switches.